The upwardly-opening box assembly associated with vehicles such as pickup trucks and the like have, for many years, employed a large plurality of stamped metal panels for defining the box. For example, in most instances the front and side panels of the box are stamped sheet steel members, and in most instances the bed of the box is also defined by one or more stamped sheet-like steel panels. Forming the box predominantly from stamped sheet steel panels, however, results in structural and economic factors which are less than desirable.
A principal disadvantage associated with using stamped sheet steel panels is the fact that such panels require use of a greater quantity of material than is optimally desired, and also ultimately results in the formed members having greater weight than desired, both of which are undesirable from the standpoint of the overall vehicle. More specifically, it is known that stamping involves forming a three-dimensional shape from a flat sheet steel of rather thin gauge, and during stamping the three-dimensional deformation of the sheet steel necessarily causes stretching of the steel, particularly at those locations which are subjected to the greatest three-dimensional deformation. This stretching can typically be in the range of from 8% to 10%, and the net effect is that the thickness of the sheet steel at the stretched locations can be significantly reduced by this degree. Such significant thickness reduction hence results in areas of the sheet being of significantly reduced strength, and hence these reduced strength areas can dictate and control the design of the overall stamped part, thereby requiring initial use of a sheet thickness greater than would otherwise be required so as to compensate for the thickness reduction caused by stretching.
Stamping large sheets to define large three-dimensional panels, such as for a vehicle box assembly, also often results in undesired surface stretch marks or blemishes in the finished product. The stamping operation also typically requires that the sheet be significantly oversized relative to the finished product so as to permit trimming of the sheet around the entire peripheral edge of the finished stamped member, and this hence results in significant waste.
A further and significantly disadvantageous factor associated with use of stamped sheet steel panels for vehicle box assemblies is the cost associated with the manufacture of the required stamping tools, and the significant number of such tools required to form the different stamped panels. Since the stamped panels defining the front and side walls of the box assembly, as well as the bed, are all of rather large size, the stamping tool required to form a single panel is necessarily large and complex, and hence extremely costly to manufacture. The complexity associated with such tooling is further increased by the fact that the side and front panels typically have reinforcing channels formed along the upper edges thereof, which channels define either inverted U-shaped configurations or sometimes even a closed hollow channel, whereby the stamping tooling for such shapes involves multiple stamping steps and hence is complex and expensive.
The cost of the stamping tooling is further exacerbated by the fact that each stamped part requires its own customized stamping tooling. For example, the front panel, the right side panel and the left side panel of the bed assembly all require their own customized tooling. Further, different tooling must be provided to permit manufacture of the right and left side panels for each different bed length. Needless to say, the overall net effect is that the tooling is not only extremely costly, but the tooling also requires significant floor space in the factory, and additional labor for operation thereof.
Several currently known constructions for vehicle box assemblies employing a significant number of stamped sheet steel panels are illustrated by FIGS. 1-4. In FIG. 1, a box assembly 10 as associated with a pickup truck employs right and left upright inner side panels 11 and 12, respectively, joined to an upright front panel 13. The bottom of the box assembly is closed by a generally horizontal bed 14 which, in this conventional construction, employs a multiple-piece construction defined predominantly by a center bed panel 15 which extends throughout the full length of the bed and has a width which generally corresponds to the transverse width between the wheel well openings. The bed regions forwardly and rearwardly of the wheel well openings are defined by separate small bed panel sections 16 and 17 which are rigidly joined, as by welding, to the center bed panel 15 and to the adjacent upright side panels. The rear of the bed assembly defines a conventional access opening which, in a known manner, is closed by a swingable tailgate. In this known construction of the bed assembly, each of the front panel, right side panel, left side panel and bed are formed as stamped steel sheet members, all different, and in fact the bed in this example is formed by a plurality (here five) of stamped members. The wheel well covers 18, which are also typically separate stampings, are welded to the respective side panel and to the bed during the assembly process. A box assembly having constructional features similar to that illustrated by FIG. 1 hence employs a large number of different stamped members, and accordingly requires large investment in tooling as well as significant factory space for production and assembly of such construction.
FIG. 2 illustrates another known construction of a box assembly which is virtually identical to the box assembly of FIG. 1 described above, except that the bed 14′ in FIG. 2 is constructed as a one-piece stamped panel having wheel well openings formed in opposite sides thereof, typically by means of a separate stamping operation, thereby eliminating the need for separate side bed panels. The construction of the box assembly of FIG. 2 is in all other respects generally similar to that illustrated by FIG. 1, and hence possesses generally the same structural and cost disadvantages.
Referring now to FIG. 3, there is illustrated improvements with respect to a box assembly for a pickup truck, which improvements are illustrated in greater detail in U.S. Pat. No. 6,644,721, owned by the Assignee hereof. The box assembly illustrated in FIG. 3 is constructed generally the same as the box assembly shown in FIG. 1 except that the center floor pan 15 in FIG. 3 is constructed as a one-piece roll-formed member which provides improved performance and weight reduction.
Considering also the box assembly illustrated in FIG. 4, this depicts another improved construction of the box assembly developed by the Assignee hereof. This improved box construction generally corresponds to the box construction of FIG. 2 except that the full-sized bed member 14′ is constructed as a roll-formed member, rather than as a stamped member. This roll-formed construction of the one-piece bed member, as disclosed in greater detail in Assignee's U.S. Pat. No. 6,128,815, has been successfully commercially adopted and is currently in use on models of pickup trucks currently being sold.
As a known alternative construction for the box assembly illustrated by FIG. 1, the side panel, the adjacent wheel well cover and adjacent front and rear side bed panels can be formed as a one-piece stamping, a different such stamping being required for each of the right and left sides of the box assembly. Such stamping, however, due to its size and complex three-dimensional shape, requires complex and costly tooling.
Accordingly, it is an object of this invention to provide an improved roll-formed component part for a vehicle box assembly, specifically a monolithic one-piece roll-formed panel member which is also transversely bent into an L-shaped longitudinal configuration so as to form both front and bed panels, which component part is believed to provide improved characteristics with respect to construction, assembly and cost efficiencies with respect to materials, assembly and tooling, and which at the same time retains or provides improved performance characteristics with respect to the assembled box assembly.
More specifically, the improved roll-formed component of the present invention is believed to provide the assembled box assembly with improvements with respect to reduction in overall weight, reduction with respect to overall usage of material, reduction with respect to material cost, simplification with respect to required assembly, handling and manipulation, significant reduction with respect to tooling costs, and an ability to utilize the same tooling to facilitate manufacture of multiple or different sized parts.
According to the present invention there is provided an improved monolithic one-piece roll-formed panel member for a vehicle bed assembly, which panel member during roll-forming thereof is provided with alternating grooves and ribs extending lengthwise of the panel member in parallel relationship, which alternating grooves and ribs are disposed sidewardly across a significant width of the panel member. After roll-forming of the panel member in the form of a substantially continuous elongate sheet, the sheet is transversely cut to define flat panel members of desired length, which length corresponds generally to the length of the vehicle bed as well as the height of the front side wall of the box assembly. The monolithic flat panel member is thereafter bent transversely thereacross through a generally 90° angle so as to define a first elongate and generally horizontal panel part which functions as a bed for the box assembly, and which is integrally and monolithically joined through the 90° bend to a shorter upright panel section which is of lesser longitudinal extent and which functions as a front side wall for the box assembly. The alternating ribs and grooves as roll-formed in the panel member extend vertically throughout the front side panel part and thence extend through the 90° bend so as to project longitudinally in the lengthwise direction of the bed panel part so as to effectively terminate at the rear edge thereof.
In the improved construction as described above, the roll-formed panel member may have a width which generally corresponds to the width of the box assembly so that the bed and front panel parts both generally correspond to and occupy the full width of the box assembly. In this variation the side portions of the bed panel part may have wheel well openings formed therein, such as by a stamping operation, to permit securement to and cooperation with separate wheel well housings. In a preferred form of this variation, the side portions of the roll-formed panel member are preferably flat (i.e., free of roll-formed ribs and grooves) so as to leave a flat edge around the wheel well opening to facilitate securement to the wheel well housing. Alternatively, in a preferred embodiment, the roll-formed panel member defining the bed and front wall panel parts may have a width which more closely corresponds to the width between the wheel well housings, in which case the box assembly is provided with front and rear bed sections (either separate from or integrally joined to the side wall panel) cooperating with the wheel well housing and the roll-formed bed panel, as well as front panel end extenders which cooperate with the roll-formed front panel so as to permit forming of the vehicle box assembly.
According to the present invention, there is provided an improved box assembly for a vehicle, such as a pickup truck, which box assembly employs a roll-formed bed panel and a roll-formed front panel which is integrally and monolithically joined to the bed panel through an approximately 90° bend section which extends transversely across the panel, and which may additionally employ a roll-formed upright side panel. The roll-forming of large panel members associated with the box assembly permits minimal usage of material in terms of both square footage of material as well as material thickness, thereby minimizing cost and weight of the box assembly, and results in panels of substantially uniform thickness throughout the longitudinal transverse directions thereof. The use of roll-formed panels is also desirable since it permits the panels to be formed from high strength steel if desired, specifically sheet steel having a yield strength in the range of from about 50,000 psi to about 100,000 psi, which high strength steel is typically not feasible for use with large stamped panels.
Other objects and purposes of the invention will be apparent to those familiar with constructions and processes similar to those described herein upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The word “upwardly” will also be used in reference to the surfaces associated with the box assembly which project upwardly when the box assembly is in its normal assembled position on a vehicle. The words “front” and “rear” will be used with reference to those directions which normally connotate the front and rear of a vehicle when the box assembly is mounted thereon. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the box assembly, or designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.